The petite powerhouse known as Shakira performed her big, bold and beautiful ballad 'Empire' on 'The Voice' last night (April 22). It was a fiery performance, quite literally, with pyro blazes igniting behind the black-clad and supremely sexy singer. But the perf did raise some questions.

First off, we love how Shak gets into it when she performs this song, touching herself, running her hands and her palms over her torso and raking her hands through her hair and flipping it around while she performs. She was also having her way with that mic stand.

She is a consummate entertainer, and it was great for her charges on 'The Voice,' on which she serves as a coach, to see her do her thing in front of their own two eyes.

But was Shakira doing it live, actually? Questions arose, and quickly, online during and after the performance. The Twitterverse was alight with tweets about a coach on a singing competition not singing live. She was accused of lip-syncing.

Granted, singers often sing to tape or use a backing track while performing on shows such as this. There are so many different layers to the vocals that they can't hit two notes at once, so there were a few parts that looked like Shak wasn't singing live. But that was to be expected.

Some of the fan tweets are below. They weren't so much mad at Shak for lipping it. In fact, the majority of tweets seemed more annoyed at the show for having a double standard. A select sample of tweets about the perf are below.